Install gdk in a new interactive shell

What does this merge request do and why?

We haven't activated mise yet so we need to run gdk install in an interactive subshell.

This should solve the issue mise not found.

Closes #2533 (closed)

How to set up and validate locally

1. Setup a fresh system user gdk
2. Allow gdk user to run sudo without password prompt: sudo echo "gdk ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/gdk_no_password
3. su - gdk
4. echo 'export MISE_DATA_DIR=$HOME/mise' >> $HOME/.bashrc
5. curl "https://gitlab.com/gitlab-org/gitlab-development-kit/-/raw/2533-mise-not-found/support/install" | bash -s gdk "2533-mise-not-found" "mise"

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This MR references an issue describing the change.
• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.